DOCSLIB.ORG

Gravity and Magnetic Features As Related to Geology in the Leadville 30-Minute Quadrangle, Colorado

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gravity and Magnetic Features As Related to Geology in the Leadville 30-Minute Quadrangle, Colorado Gravity and Magnetic Features as Related to Geology in the Leadville 30-Minute Quadrangle, Colorado GEOLOGICAL SURVEY PROFESSIONAL PAPER 726-C Gravity and Magnetic Features as Related to Geology in the Leadville 30-Minute Quadrangle, Colorado By OGDEN TWETO and J. E. CASE GEOPHYSICAL FIELD INVESTIGATIONS GEOLOGICAL SURVEY PROFESSIONAL PAPER 726-C A summary and correlation of geologic and geophysical data on the most productive part of the Colorado mineral belt UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1972 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 72-600032 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 2401-2145 CONTENTS Page Page Abstract...... ------------------------------------------------------------------------------- C1 Gravity features .... ·------------------------------------------------------------------ C16 Introduction .............................................................................. 1 Gravity surveY------------------------------------------------------------------ 16 · Geology ____________________________________________________________________________________ : __ 3 Errors in the Bouguer anomalies _________________________ _ 17 Major features .......... -------------------------------------------------------- 3 Interpretation of the gravity anomaly map _______________________ _ 18 Precambrian rocks __________________________________________________________ _ 3 ..,. Mineral-belt gravity low________________________________________________ _ 18 Sedimentary rocks ___________________________________________________________ _ 4 Underlying batholith as source ............................. 18 Upper Cretaceous and Tertiary intrusive rocks ........ 4 Deep crustal or subcrustal source........................ 20 Tertiary volcanic rocks __________________________________________________ _ 7 Local anomalies along the mineral-belt low _______________ _ 20 Structure... ------------------------------------------------------------------------- 8 Gravity low over the Arkansas valley graben ............ 22 Precambrian Homestake shear zone ____________________ _ 8 Other bedrock anomalies ________________________________________________ _ 22 Laramide and younger structure .......................... 8 Aeromagnetic survey______________________________________________________________ _ 24 Geology of the Arkansas valley bottom....................... 9 Interpretation of the magnetic map .... --------------------·------------ 24 Ore deposits----------------------------------------------------------------------- 11 General features of the magnetic map ________________________ _ 24 Densities and magnetic properties of the Anomalies over the Arkansas valleY----------------------------· 25 major rock units----------------------------------------------------------- 12 Anomalies related to the Homestake shear zone ........ 25 Densities ____________________________________________________________________________ . 13 Anomalies along the Sawatch Range ........................... 25 Magnetic properties--------------------------------------------------------- 14 Anomalies in the southern Gore Range ....................... 26 Precambrian gneiss ........... --------------------------------------· 15 Anomalies along the Mosquito-Tenmile Range __________ _ 26 Precambrian granitic rocks·----------------------------------· 15 Anomalies in the eastern part of the quadrangle ...... 27 Paleozoic sedimentary rocks·---------------------------------· 15 Summary and conclusions .... --------------------------------------------------· 27 Upper Cretaceous and Tertiary intrusive rocks. 16 References cited .. ---------------------------------------------------------------------- 29 ILLUSTRATIONS Page PLATE 1. Geologic and Bouguer anomaly map and sections of the Leadville 30-minute quadrangle, central Colorado.... -----------------------------------------------------------------------------------------------------------------------------------------------------In pocket 2. Aeromagnetic map and profiles of the Leadville 30-minute quadrangle ________________________________________________________________ ln pocket FIGURE 1. Index map of Colorado __________________________________________________ -------------------------------------------------------------------------------------------------------· C2 2. Sketch map showing major structural features ........ -------------------------------------------------------------------------------------------------------· 6 3. Histogram showing densities of major rock units·----------------------------------------------------------------------------------------------------------· 12 4. Histogram showing magnetic susceptibilities of major rock units ...... --------------------------------------------------------------------------· 13 5. Regional Bouguer anomaly maP----------------------------------------------------------------------------------------------------··---------------------·---·---------· 17 6. Section showing interpretation of regional gravity anomalY------------------------------------------·--·------------------------------------------ 19 7. Section showing gravitation effects of a deep crustal-mass deficiency beneath the Colorado mineral belt............ 21 8. Map and section showing residual gravity anomaly over the Arkansas valley graben and its interpretation.... 23 TABLES Page TABLE 1. Generalized geologic column, Leadville 30-minute quadrangle ........... --------------------------------·-----------------------------------------· C5 2. Summary of magnetic properties of the major rock units--------------------------------------------------------------------------------------------- 15 III GEOPHYSICAL FIELD INVESTIGATIONS GRAVITY AND MAGNETIC FEATURES AS RELATED TO GEOLOGY IN THE LEADVILLE 30-MINUTE QUADRANGLE, COLORADO By OGDEN TWETO and J. E. CASE ABSTRACT stock of Tertiary porphyry. Magnetic highs and lows occur Regional gravity and aeromagnetic surveys were made in both over Precambrian granitic and gneissic rocks and over the Leadville 30-minute quadrangle, Colorado, to supplement porphyry intrusives. The magnetic susceptibilities of these and extend geologic studies in a highly productive segment of rocks have overlapping ranges; thus, many of the anomalies the Colorado mineral belt. The quadrangle lies at the inter­ can be confidently interpreted only where the sources are section of the mineral belt with the Arkansas valley graben, exposed. Many magnetic highs correlate with topographic a northern extension of the Rio Grande and San Luis Valley highs developed in crystalline rocks, but other highs are graben system of New Mexico and southern Colorado. nearly independent of topography, and reflect strong mag­ Almost the entire quadrangle is a part of the eastern flank netization of the rocks. of the huge Sawatch anticline. The Sawatch Range, in the The Precambrian Homestake shear zone, which trends western part of the area, is carved in the Precambrian rocks northeast in the northwestern part of the quadrangle, is ex­ in the core of this anticline. The Arkansas River valley, at the pressed by a strong magnetic gradient that reflects magnetic foot of the range, is an elongate downfaulted block, or graben, biotite gneiss and migmatite within, and northwest of, the high on the eastern flank of the anticline. The Mosquito and shear zone, and less magnetic amphibole and quartz gneiss Tenmile Ranges, which occupy a broad central belt through southeast of the shear zone. The gradient indicates both con­ the length of the quadrangle, constitute an upthrown fault tinuity and location of the shear zone beneath areas covered block east of the Arkansas valley graben. They consist of by Paleozoic sedimentary rocks. Precambrian rocks capped by Paleozoic sedimentary rocks. Magnetic and gravity highs are found over a fault block The sedimentary rocks dip eastward into South Park, a broad near Sheep Mountain and Round Hill, reflecting dense and structural basin. magnetic rocks, possibly mafic intrusives, in the block. Gravity The Precambrian rocks and the Paleozoic sedimentary rocks and magnetic lows are found in the southeastern part of the are cut by numerous bodies of intrusive porphyry of Late quadrangle, where Paleozoic rocks are several thousand feet Cretaceous and Tertiary age. These porphyry bodies and re­ thick. lated mineral deposits- such as those of Climax, Leadville, Neither the Climax nor the Leadville mining district has a and several other mining districts - characterize the Colorado gravity or total-intensity-magnetic expression, but both are mineral belt, which here forms a broad northeast-trending belt marked by weak residual magnetic lows, probably reflecting that occupies much of the quadrangle. A deep fill of upper alteration of the crystalline rocks. Many of the mining dis­ Tertiary alluvial deposits and mantling Pleistocene glacial tricts are located near the axis of the main gravity low, and, deposits in the Arkansas valley covers the bedrock along the thus, it may be postulated that mineralization arose from the axial trend of the mineral belt for several miles southwest of apical region of the batholith at depth. Leadville. The dominant gravity anomaly is a huge low of 30-50 INTRODUCTION milligals which trends northeast across the quadrangle. From analysis of steep gradients on the flanks
Load more

Recommended publications
  • Statement of Dan Gibbs Executive Director Colorado Department Of
    Statement of Dan Gibbs Executive Director Colorado Department of Natural Resources Before The Subcommittee on National Parks, Forests, and Public Lands of The House Natural Resources Committee April 2, 2019 Chairwoman Haaland, Ranking Member Young, and Members of the Subcommittee: On behalf of Governor Polis and the State of Colorado, we appreciate the opportunity to provide testimony on the Colorado Outdoor Recreation and Economy Act (H.R. 823). We strongly support the CORE Act and hope Congress will move swiftly to enact it. Governor Polis would have liked to be here today with his former colleagues to express his strong support for this legislation. As you know, as a member of Congress, Governor Polis had sponsored the Continental Divide Recreation, Wilderness and Camp Hale Legacy Act, which has now been incorporated into the broader CORE Act. Introduction This legislation—the product of years of collaboration among elected officials, businesses, community members, and a myriad of other interested and affected stakeholders across Colorado—would protect some of the most beloved public lands in Colorado for their unsurpassed recreation, scenery, wildlife, watersheds, historic, and other unique values. As the Executive Director of the Colorado Department of Natural Resources, I support this bill because it will benefit our wildlife by protecting critical habitat and migration corridors; it will protect the outstanding recreational experiences that bring people from across Colorado—and the world—to these special places; it will help safeguard Colorado’s water resources by protecting key watersheds and all water rights; it strikes the right balance by protecting key public lands from development, while protecting all existing mineral rights and leaving other appropriate lands available for mining, oil, and gas development; and because it complements the values and opportunities associated with our state lands.
    [Show full text]
  • Mountain Goat Unit Management Plan | Wasatch and Central Mountains
    MOUNTAIN GOAT UNIT MANAGEMENT PLAN Wasatch and Central Mountains Lone Peak / Box Elder Peak / Timpanogos / Provo Peak / Nebo August 2019 BOUNDARY DESCRIPTIONS Lone Peak – Salt Lake County: Boundary begins at the junction of I-15 and I-80 in Salt Lake City; east on I-80 to the Salt Lake-Summit county line; south along this county line to the Salt Lake-Wasatch county line; southwest along this county line to the Salt Lake-Utah county line; southwest along this county line to I-15; north on I-15 to I-80 in Salt Lake City. Box Elder Peak – Utah County: Boundary begins at I-15 and the Salt Lake-Utah county line; east along this county line to the Utah-Wasatch county line; south along this county line to “Pole Line Pass” on the Snake Creek-North Fork American Fork Canyon road; west on this road to SR-92; west on SR-92 to I-15; north on I-15 to the Salt Lake-Utah county line. Timpanogos – Utah County: Boundary begins at the junction of SR-92 and SR-146; southeast on SR-92 to US-189; southwest on US-189 to SR-52; west on SR-52 to US-89; north on US-89 to SR-146; north on SR-146 to SR-92. Provo Peak – Utah County: Boundary begins at the junction of I-15 and US-6 at Spanish Fork; north on I-15 to SR-52; east on SR-52 to US-189; northeast on US-189 to the South Fork Drainage of Provo Canyon; east along this drainage bottom to the Berryport trail; south along this trail to the Left Fork of Hobble Creek road; south on this road to the Right Fork of Hobble Creek road; east on this road to Cedar Canyon; south along this canyon bottom to Wanrhodes Canyon; south along this canyon bottom to Diamond Fork Creek; southwest along this creek to US-6; northeast on US-6 to I-15.
    [Show full text]
  • Primitive Areas Gore Range-Eagles Nest And
    OC1 LO STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS OHIO GEOLOGICAL SURVEt OCT 2 r iQ70 GORE RANGE-EAGLES NEST AND VICINITY, COLORADO GEOLOGICAL SURVEY BULLETIN 1319-C f* MINERAL RESOURCES of the GORE RANGE-EAGLES NEST PRIMITIVE AREA and VICINITY, COLORADO Crest of Gore Range and head of middle fork of Black Creek. View is westward. Mount Powell (alt 13,534 ft) is massive peak at right of cen­ ter. Eagles Nest Mountain is at far right. Duck Lake is in right foreground. Trough above right end of lake marks fault zone of north-northwest trend. Dark area on steep front of rock glacier at left in photograph is typical "wet front" suggesting ice core in rock glacier. Mineral Resources of the Gore Range-Eagles Nest Primitive Area and Vicinity, Summit and Eagle Counties, Colorado By OGDEN TWETO and BRUCE BRYANT, U.S. GEOLOGICAL SURVEY, and by FRANK E. WILLIAMS, U.S. BUREAU OF MINES c STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS GEOLOGICAL SURVEY BULLETIN 1319-C An evaluation of the mineral potential of the area UNITED STATES GOVERNMENT PRINTING OFFICE. WASHINGTON : 1970 UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director Library of Congress catalog-card No. 78-607129 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 ^. STUDIES RELATED TO WILDERNESS PRIMITIVE AREAS The Wilderness Act (Public Law 88-577, Sept. 3, 1964) and the Conference Report on Senate bill 4, 88th Congress, direct the U.S. Geological Survey and the U.S. Bureau of Mines to make mineral surveys of wilderness and primitive areas.
    [Show full text]
  • Trails Plan | 2009 Town of Breckenridge | Trails Plan
    TOWN OF BRECKENRIDGE | TRAILS PLAN | 2009 TOWN OF BRECKENRIDGE | TRAILS PLAN TOWN OF BRECKENRIDGE TRAILS PLAN Introduction 4 Plan Philosophy 4 Plan Prioritization 5 Plan Goals and Objectives 5 Role of the Plan 5 Plan Assumptions 6 Plan Implementation 6 Plan Organization 6 How This PlanW as Developed 6 Winter and Summer Elements 7 Disclaimer 7 Planning Areas 7 Area 1: Ski Hill Road/Peak 7/8 Base Area 7 Peaks Trailhead and Trails 7 Freeride Park 8 Shock Hill/Nordic Center 8 Cucumber Gulch Preserve 9 Claimjumper/Recreation Center Connection 9 Peak 7 Neighborhood Connection 10 New Nordic World/Peak 6 Expansion 10 Iowa Hill Trailhead 10 American Way Access 10 Area 2: Core/Upper Four Seasons Area 11 Riverwalk Connection 11 Klack Placer 11 The Cedars/Trails End Connection 11 F&D Placer to Burro Connection 12 Maggie Pond Access 12 Four O’Clock Ski Run 12 Timber Trail 12 Maggie Placer Trail 13 Area 3: Breckenridge South 13 Aspen Grove/Aspen Alley Trail 13 Wakefield Trailhead 13 Little Mountain 13 Blue River/Hoosier Pass Recpath 14 The Burro Trail Accesses 14 Bekkedal/Gold King (lots 1&2) to Burro Connection 14 Ski Area Equestrian Trails 14 Now Colorado/Silver Queen Connection 15 Riverwood Trail 15 PAGE 1 TRAILS PLAN | TOWN OF BRECKENRIDGE TOWN OF BRECKENRIDGE | TRAILS PLAN Area 3: Breckenridge South (continued) Breckenridge Park Estates Trailhead 15 Fredonia Gulch Trailhead 16 Bemrose Ski Circus 16 Wheeler Trail Resurrection 16 Pennsylvania Gulch and Indiana Creek Road Winter Access 16 Spruce Creek Trail Spur 16 Lehman Gulch Trail 17 Monte Cristo
    [Show full text]
  • Workshop Proceedings
    This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. ALPINE BIRD COMMUNITIES OF WESTERN NORTH AMERICA: IMPLICATIONS FOR MANAGEMENT AND RESEARcH!/ Clait E. Braun Wildlife Researcher Colorado Division of Wildlife, Research Center, 317 West Prospect Street, Fort Collins, Colorado 80526 ABSTRACT The avifauna of alpine regions of western North America is notably depauperate. Average community size is normally 3 to 4 although 5 species may consistently breed and nest above treeline. Only 1 species is a year around resident and totally dependent upon alpine habitats. Seasonal habitat preferences of the breeding avifauna are identified and the complexity of the processes and factors influencing alpine regions are reviewed. Management problems are discussed and research opportunities are identified. KEYWORDS: alpine ecosystem, habitat, avifauna, management, western North America. INTRODUCTION Alpine ecosystems occur in most of the high mountain cordilleras of western North America. Alpine, as used in this paper, refers to the area above treeline where habitats are characterized by short growing seasons, low temperatures and high winds. The term "tundra" is frequently used to describe these habitats but is more properly used in connection with arctic areas north of the limit of forest growth (Hoffmann and Taber 1967). While use of the terms "alpine tundra" and "arctic tundra" is common in designating above treeline (alpine) and northern lowland areas (arctic), the terminology of Billings (1979) is preferred. Likewise, lumping of alpine and arctic ecosystems into the "tundra biome" (see Kendeigh 1961) is not really feasible because of the extreme differences in radiation, moisture, topography, photo­ period, presence or absence of permafrost, etc.
    [Show full text]
  • Old Spanish National Historic Trail Final Comprehensive Administrative Strategy
    Old Spanish National Historic Trail Final Comprehensive Administrative Strategy Chama Crossing at Red Rock, New Mexico U.S. Department of the Interior National Park Service - National Trails Intermountain Region Bureau of Land Management - Utah This page is intentionally blank. Table of Contents Old Spanish National Historic Trail - Final Comprehensive Administrative Stratagy Table of Contents i Table of Contents v Executive Summary 1 Chapter 1 - Introduction 3 The National Trails System 4 Old Spanish National Historic Trail Feasibility Study 4 Legislative History of the Old Spanish National Historic Trail 5 Nature and Purpose of the Old Spanish National Historic Trail 5 Trail Period of Significance 5 Trail Significance Statement 7 Brief Description of the Trail Routes 9 Goal of the Comprehensive Administrative Strategy 10 Next Steps and Strategy Implementation 11 Chapter 2 - Approaches to Administration 13 Introduction 14 Administration and Management 17 Partners and Trail Resource Stewards 17 Resource Identification, Protection, and Monitoring 19 National Historic Trail Rights-of-Way 44 Mapping and Resource Inventory 44 Partnership Certification Program 45 Trail Use Experience 47 Interpretation/Education 47 Primary Interpretive Themes 48 Secondary Interpretive Themes 48 Recreational Opportunities 49 Local Tour Routes 49 Health and Safety 49 User Capacity 50 Costs 50 Operations i Table of Contents Old Spanish National Historic Trail - Final Comprehensive Administrative Stratagy Table of Contents 51 Funding 51 Gaps in Information and
    [Show full text]
  • Biotic Communities of the Southern Wasatch and Uinta Mountains, Utah C
    Great Basin Naturalist Volume 6 Article 1 Number 1 – Number 4 11-15-1945 Biotic communities of the southern Wasatch and Uinta Mountains, Utah C. Lynn Hayward Brigham Young University, Provo, Utah Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Hayward, C. Lynn (1945) "Biotic communities of the southern Wasatch and Uinta Mountains, Utah," Great Basin Naturalist: Vol. 6 : No. 1 , Article 1. Available at: https://scholarsarchive.byu.edu/gbn/vol6/iss1/1 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. .. The Great Basin Naturalist Published by the Department of Zoology and Entomology Brigham Young University, Provo, Utah X'oi.iMK \'\ X()VP:MP.KR 15, 1945 Nos. 1-4 BTOTTC COMMUNITIES OF THE SOUTHERN WASATCH AND UINTA MOUNTAINS, UTAH"' C. T.YXN HAYWARD(^) Associate Professor of Zoology P.rijiham Young University Table of Contents 1. INTRODUCTION 2 A. Scope and Nature of Problem 2 B. Methods 4 C. Review of Previous Work 8 IP TOPOGRAPHY AND GEOLOGY 9 A. Location and General Topography 9 B. Geological Histor}- 11 C. Glaciation 13 III. CLIMATE 13 A. Gene^^l Climate of Wasatch Mountains 13 P>. Climate of Mt. Timpanogos and L'intas 15 1 Temperature 15 2. Precipitation Pt 3. Relative Humidity 1/ ' 4. Wind 18 5. General Discussion 18 IV. CONCEPTS OF BIOTTC COMMUNITIES 1c> \-.
    [Show full text]
  • Structure of Alpine Plant Communities Near King's Peak, Uinta Mountains, Utah
    Great Basin Naturalist Volume 42 Number 1 Article 3 3-31-1982 Structure of alpine plant communities near King's Peak, Uinta Mountains, Utah George M. Briggs University of Montana, Missoula James A. MacMahon Utah State University Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Briggs, George M. and MacMahon, James A. (1982) "Structure of alpine plant communities near King's Peak, Uinta Mountains, Utah," Great Basin Naturalist: Vol. 42 : No. 1 , Article 3. Available at: https://scholarsarchive.byu.edu/gbn/vol42/iss1/3 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. STRUCTURE OF ALPINE PLANT COMMUNITIES NEAR KING'S PEAK, UINTA MOUNTAINS, UTAH George M. Briggs' and James A. MacMahon- Abstract.- a study was made at 18 sites with elevations between 3512 and 3768 m in the Uinta Mountains, Utah. Sites were small in extent but typified vegetation patterns found in the Uintas. Standing crop, species compo- sition (based on dry weight), and values for several physical parameters were determined at each site. Simple linear regressions performed between the various biotic and abiotic characters revealed significant relationships between the characteristics of rocks visible at the surface (the number, size, and variation in size) and vegetation cover. This relationship was probably due to the burial of rocks as a region became vegetated. Bray and Curtis ordinations per- formed on the indicated data that there were several factors which influenced the species composition but that no single factor dictated the vegetational pattern.
    [Show full text]
  • COLORADO MAGAZINE Published Quarterly by Vol
    The State Historical Society of Colorado THE COLORADO MAGAZINE Published Quarterly by Vol. XXXIX Denver, Colorado, October, 1962 Number 4 Gold Boats on The Swan The Story of Ben Stanley Revett, Gold Dredger By Belle Turnbull* At the time that the material for use in writing about Revett was first examined, a number of papers were kept for reference. Of other papers, notes were made and the papers returned to Mrs. Melissa Hayden. At the time, since the objective was to use the notes for background in a story, notes were made sometimes without much attention to dates and sources, though they were kept in chronological order by year, only. For color and background the author is deeply indebted to the following, not one of whom is still living in 1962: George Robinson, dredgemaster, and later County Treasurer of Summit County and Mayor of Breckenridge; Mrs. Melissa Hayden, widow of Revett's secre­ tary, and herself Clerk of the District Court for many years; and George Robert Johnson, mining engineer, who permitted my presence on a gold dredge against the wishes of his swing shift crew, to whom a woman on board was anathema. Mr. Johnson's explanations of the operation of a gold dredge were lucid and helpful, even to a woman author. Thanks are also due to Gordon Goodridge, who dug in the Summit County records for data on placer grounds.-Author. In the history of deep mining for gold in Colorado, Ben Stanley Revett ranks as First Gold Dredger. Not only was he the first to carry through the financing, the building, and the management of the first dredge in Colorado to dig for gold; his resourcefulness and bulldog tenacity drove him on, year after year, to finish what he had begun: to find the best possible method of driving to bedrock and to bring up the gold.
    [Show full text]
  • The Rockies of Colorado
    THE ROCKIES OF COLORADO THE ROCKIES OF COLORADO BY EVELIO ECHEVARRfA C. (Three illustrations: nos. 9- II) OLORADO has always been proud of its mountains and rightly so; it is often referred to in the Union as 'the mountain state', about 6o per cent of its area is mountainous, and contains fifty-four peaks over 14,ooo ft. and some three hundred over 13,000 ft. Further, its mountaineering history has some unique aspects. And yet, Colorado's mountains have been seldom mentioned in mountaineering journals; if in modern times they may have deserved a passing mention it has been because of a new route on Long's Peak. But on the whole, the Rockies of Colorado are almost unrecorded in the mountaineering world abroad. In this paper, an effort has been made to outline briefly the characteris­ tics of this area, and to review its mountaineering past; a few personal experiences are also added. The mountains of Colorado belong almost completely to the Rocky Mountain range of North America; a few outliers are sometimes mentioned as independent lesser chains, but in features and heights they are unimportant. The Rockies of Colorado are grouped into a number of ranges (see sketch-map), some of which are actually prolongations of others. Some­ what loosely and with some injustice to precise geography, they can be grouped into ten important sections. The state of Colorado is a perfect rectangle in shape; the Rockies enter into its western third from Wyoming, to the north, and split, then, into two parallel chains which unite in the centre of the state.
    [Show full text]
  • Ce Standards Outlined in FHWA’S Monitoring Plan and As Required by the USACE Section 404 Permit Conditions
    Fremont Pass Rec Pathway Figure 1. Project Location and Vicinity 2 Fremont Pass Rec Pathway Purpose and Need The purpose of the proposed project is to improve the safety of cyclists traveling along State Highway (SH) 91 in Tenmile Canyon. Currently, cyclists travelling south from Copper Mountain toward Fremont Pass must ride on SH 91 through Tenmile Canyon. This situation presents safety concerns for cyclists and drivers through this approximately 3.3-mile segment of highway as it has limited shoulder widths, tight curves, high speeds, and short line of sight distances. In addition, there is a need to provide additional multi-use pathways in Summit County, Colorado. Not only does Summit County aim to accomplish its objectives to maintain, enhance, connect, and expand the recreation pathway system, the Tenmile Canyon corridor south of Copper Mountain has been identified as a high priority pathway in Governor Hickenlooper’s “Colorado the Beautiful: Colorado’s 16” trails initiative. The recreation pathway system in Summit County continues to experience increased demand and utilization. The proposed project would complement the current recreation pathway in Summit County by offering an extension of this system with the proposed pathway towards Fremont Pass. In addition to benefiting cyclists, the multi-modal pathway will allow walkers, runners, and other non-motorized recreational users to access this section of Tenmile Canyon. Description of the Proposed Action Construction of the new recreation pathway would be on National Forest system lands managed by the USFS. The proposed pathway alignment would use the existing, abandoned railroad grade in Tenmile Canyon. This alignment is on the east side of both Tenmile Creek and SH 91.
    [Show full text]
  • Wilderness Areas on the Uinta-Wasatch-Cache National
    Wilderness Areas On The Uinta‐Wasatch‐Cache National Forests “Wilderness is the land that was wild land beyond the frontier...land that shaped the growth of our nation and the character of its people. Wilderness is the land that is rare, wild places where one can retreat from civilization, reconnect with the Earth, and find healing, meaning and significance.” The United States was the first country to define and create designated wilderness areas. In 1964 the Wilderness Act was passed in congress. The Act describes wilderness as the following: "...lands designated for preservation and protection in their natural condition..." Section 2(a) "...an area where the earth and its community of life are untrammeled by man..." Section 2(c) "...an area of undeveloped Federal land retaining its primeval character and influence, without permanent improvement or human habitation..." Section 2(c) "...generally appears to have been affected primarily by the forces of nature, with the imprint of man's work substantially unnoticeable..." Section 2(c) "...has outstanding opportunities for solitude or a primitive and unconfined type of recreation..." Section 2(c) "...shall be devoted to the public purposes of recreation, scenic, scientific, educational, conservation and historic use." Section 4(b) Within the Uinta‐Wasatch‐Cache National Forest there are 9 designated wilderness areas. These areas include: Mount Naomi Wilderness, Wellsville Mountain Wilderness, Mount Olympus Wilderness, Twin Peaks Wilderness, Lone Peak Wilderness, Mount Timpanogos Wilderness, Mount Nebo Wilderness, Deseret Peak Wilderness and the High Uinta Wilderness. Each of these areas offer unique wilderness opportunities and experiences. The Mount Naomi Wilderness was designated in 1984 and includes 44,523 acres.
    [Show full text]